3 of the 4 door locks failed to work as intended, i.e., with fob and had to be manually manipulated to open doors. one door could be opened with key. one door could only be opened if lock was pulled up manually - it would lock automatically, but took manual intervention to get the lock in the un-lock position. unless there was an adult in this position to open the lock, the door could not be accessed from the outside. this was a rear passenger door and caused great concern when children were in the car. i have had the 3 locks replaced at a great dollar cost, but could not in good conscience have children in the rear seat without having it done. i have requested reimbursement from gmc as i do not believe a 75% failure rate on door locks is acceptable safe performance of this vehicle. *tr